Description of material examined. Up to 13 mm long, 2.5 mm wide, with eight thoracic and numerous abdominal chaetigers. Live specimens show bright colour pattern and a broad variation of colour pigments, the dominant colour in some being red, and in others, white ( Fig. 20
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D–E); white and yellow spots are scattered along the body, especially in thoracic segments ( Fig. 20
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D, F). Preserved specimens with no pigmentation or only a few reddish spots on the radiolar crown. Radiolar crown with semicircular basal lobes. Dorsal and ventral basal flanges absent. Basal membrane absent. Radioles with smooth outer margins, without flanges (only incipient in juveniles). Six to eight rows of vacuolated cells supporting radioles basally. Radiolar eyes absent. Dorsal lips with long radiolar appendages, one pair of pinnular appendage. Ventral lips and parallel lamellae present, ventral sacs absent. Posterior peristomial ring collar up to the base or radiolar crown, with dorsal margins separated by a wide gap ( Fig. 20
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F), ventral lappets separated by a midventral incision ( Fig. 20
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D). Thoracic ventral shields separated from thoracic tori by a gap ( Fig. 20
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D). Interramal eyes absent. Collar chaetae elongate, narrowly-hooded, in two oblique rows. Following thoracic chaetiger with conical notopodia; superior thoracic chaetae elongate narrowly-hooded; inferior broadly-hooded (type B). Thoracic uncini with 8–10 rows of teeth over main fang, covering slightly over half its length, with well developed breast and long handle. Companion chaetae with enlarged subdistal end with dentate appearance, and with thin distal mucro compressed laterally. Abdominal neurochaetae narrowly-hooded. Abdominal uncini with around seven rows of teeth over the main fang covering half its length, well developed breast and a short handle. Pygidium as a rim with a ventral anus and several red eyespots present on both sides. Pygidial cirrus absent. Tube unknown.

Remarks. Parasabella japonica, and the specimens studied herein, are characterised by having ventral shields separated from tori by a wide gap, long and slender inferior thoracic chaetae (type B), thoracic uncini with long handles, and a collar with conspicuous and pointed ventral lappets ( Moore & Bush 1904; Capa & Murray 2015). These combined features are unique to this species when compared with other species reported from Australia ( Capa & Murray 2015).